Population growth sometimes can take on negative connotations, such as in third-world countries where brimming populations tax resources beyond limits. However, many believe population growth has positive effects on societies. These include economic benefits such as expansion of tax bases and increased consumer spending at local businesses, as well as innovations by cultures seeking to keep up with growing populations.

History of the Population Argument

Two general schools of thought surround the perceived effects of population growth. Thomas Malthus theorized in 1798 that too much population growth too fast would overtax the Earth’s resources and eventually lead to disease, starvation and death. But more recent theories suggest that population growth can have just as many positive impacts as negative.

Economic Boost

Several scholars of the modern era have pointed to the economic benefits of population growth. In the last three decades of the 20th century, the Harvard Initiative for Global Health reported that per capita incomes grew by two-thirds with the doubling of the world’s overall population.

Another sign of prosperity from population growth can be seen in countries improving their trade structures.

Meanwhile, many economists argue that population growth leads to more property tax dollars, school funding, revenue for local businesses and federal grants flowing to local coffers.

Increased Innovation

Population growth opponents often have decried the burden on resources. However, Danish economist Ester Boserup has argued that growing populations pressure society to innovate in order to better serve the masses. For instance, high-yield crops were developed to increase food production largely in response to growing populations.

Population Growth as a Sign of Social Health

Although not a direct effect of population growth, growing societies often signify healthy societies. For instance, population growth often signals lower mortality rates through advances in medicine and science.

The Key Role of Policy

For population growth to yield positive effects, nations experiencing the growth must have sound policies to direct it. Countries that can develop better health care and medicine, strong economic plans and other social improvements that keep pace with population growth will thrive.

As the century begins, natural resources are under increasing pressure, threatening public health and development. Water shortages, soil exhaustion, loss of forests, air and water pollution, and degradation of coastlines afflict many areas. As the world’s population grows, improving living standards without destroying the environment is a global challenge.

Most developed economies currently consume resources much faster than they can regenerate. Most developing countries with rapid population growth face the urgent need to improve living standards.

Environment getting worse:

In the past decade in every environmental sector, conditions have either failed to improve, or they are worsening:

Public health:
Unclean water, along with poor sanitation, kills over 12 million people each year, most in developing countries. Air pollution kills nearly 3 million more. Heavy metals and other contaminants also cause widespread health problems.

Food supply:
Will there be enough food to go around? In 64 of 105 developing countries studied by the UN Food and Agriculture Organization, the population has been growing faster than food supplies. Population pressures have degraded some 2 billion hectares of arable land — an area the size of Canada and the U.S.

Freshwater:
The supply of freshwater is finite, but demand is soaring as population grows and use per capita rises. By 2025, when world population is projected to be 8 billion, 48 countries containing 3 billion people will face shortages.

Coastlines and oceans:
Half of all coastal ecosystems are pressured by high population densities and urban development. A tide of pollution is rising in the world’s seas. Ocean fisheries are being over exploited, and fish catches are down.

Forests:
Nearly half of the world’s original forest cover has been lost, and each year another 16 million hectares are cut, bulldozed, or burned. Forests provide over US$400 billion to the world economy annually and are vital to maintaining healthy ecosystems. Yet, current demand for forest products may exceed the limit of sustainable consumption by 25%.

Biodiversity:
The earth’s biological diversity is crucial to the continued vitality of agriculture and medicine — and perhaps even to life on earth itself. Yet human activities are pushing many thousands of plant and animal species into extinction. Two of every three species is estimated to be in decline.

Global climate change:
The earth’s surface is warming due to greenhouse gas emissions, largely from burning fossil fuels. If the global temperature rises as projected, sea levels would rise by several meters, causing widespread flooding. Global warming also could cause droughts and disrupt agriculture.

Population and sustainable development

Environmentalists and economists increasingly agree that efforts to protect the environment and to achieve better living standards can be closely linked and are mutually reinforcing. Slowing the increase in population, especially in the face of rising per capita demand for natural resources, can take pressure off the environment and buy time to improve living standards on a sustainable basis.3,8,11,12

As population growth slows, countries can invest more in education, health care, job creation, and other improvements that help boost living standards.11 In turn, as individual income, savings, and investment rise, more resources become available that can boost productivity. This dynamic process has been identified as one of the key reasons that the economies of many Asian countries grew rapidly between 1960 and 1990.5

In recent years fertility has been falling in many developing countries and, as a result, annual world population growth has fallen to about 1.4% in 2000 compared with about 2% in 1960. The UN estimated recently that population is growing by about 78 million per year, down from about 90 million estimated early in the 1990s.10 Still, at the current pace world population increases by about 1 billion every 13 years. World population surpassed 6 billion in 1999 and is projected to rise to over 8 billion by 2025.

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Globally, fertility has fallen by half since the 1960s, to about three children per woman.10 In 65 countries, including 9 in the developing world, fertility rates have fallen below replacement level of about two children per woman.9 Nonetheless, fertility is above replacement level in 123 countries, and in some countries it is substantially above replacement level. In these countries the population continues to increase rapidly. About 1.7 billion people live in 47 countries where the fertility rate averages between three and five children per woman. Another 730 million people live in 44 countries where the average woman has five children or more.7

Almost all population growth is in the developing world. As a result of differences in population growth, Europe’s population will decline from 13% to 7% of world population over the next quarter century, while that of sub-Saharan Africa will rise from 10% to 17%. The shares of other regions are projected to remain about the same as today.6

As population and demand for natural resources continue to grow, environmental limits will become increasingly apparent.6 Water shortages are expected to affect nearly 3 billion people in 2025, with sub-Saharan Africa worst affected.2 Many countries could avoid environmental crises if they took steps now to conserve and manage supplies and demand better, while slowing population growth by providing families and individuals with information and services needed to make informed choices about reproductive health.

Family planning programs play a key role. When family planning information and services are widely available and accessible, couples are better able to achieve their fertility desires.4 “Even in adverse circumstance — low incomes, limited education, and few opportunities for women — family planning programs have meant slower population growth and improved family welfare,” the World Bank has noted.1

The effects of population growth are varied and vast. While population growth, of any species, may be beneficial to a certain extent, there may come a time when the number in the populationexceeds the natural resources available to sustain it. This is referred to as overpopulation. The consequences of such an event are severe and major.

The population growth of any animal, if left uncontrolled can become burdensome. Farmers have noted, for many centuries, what the effects of an uncontrolled predator population can do to livestock. Once their natural prey run out, or are harder to find, the predators may turn to domesticated animals, despite the risks. This can cause a severe hardship on any family depending on those animals for survival.

However, when most think of a growing population, they do not think of other animals. The prime fear in most people’s minds is the population growth of their own species. As humans leave a much larger footprint on the environment than any other creature, uncontrolled overgrowth can be especially devastating.

First, as the population grows the opportunities for quality, available housing may become an issue. More people crowded into less space is not a good combination in any locality. As space is taken up, it becomes more valuable. Eventually, it begins to affect to poorest in the area. In the long run the effect of population growth may be substandard housing or homelessness.

In other cases, access to food and clean water may be the main issue. This is an even more immediate problem than housing. As more people are faced with unsanitary sources of food, disease and famine begin to take root. If left unaffected, it will sweep through an entirepopulation. In some cases, entire countries may be affected by the situation. Finding a solution often requires a multi-national effort.

Another negative effect of population growth is waste control. When there are relatively few people, controlling waste is a much simpler task. However, as populations grow, the waste increases dramatically. Finding a spot for this waste, or treating it in a way that does not poison the environment, is critically important. Regions of the world that do not have the ability to do this will find it leads to a number other serious issues and becomes a massive public health problem.

In general, the problem is not population growth in itself, it is a mismanagement of natural resources and waste that cause the majority of the problems. Many places have found effective strategies for dealing with such issues. Other locations, usually because of a lack of relative wealth, and perhaps engineering knowledge, have fallen behind.